Knowing how you use your iPad (and if I'm not mistaken you currently have an original iPad) I can understand your point of view. I'm guessing that all those PDF's you stare at may be significantly easier on your eyes on the new iPad.
And I don't think many have given Apple sufficient credit for maintaining the iPad's battery life with the new display and faster processor while sacrificing so little in terms of weight and size. That's some seriously good engineering.
As for what I'm waiting for, I can't really say. My iPad 2 serves me so well that I'm really hard put to come up with any earth shaking improvements that would not involve serious penalties in terms of weight or cost. (i.e pressure sensitive screen, e-ink options, etc.) or are simply not going to be allowed by Apple (i.e. greater customization of the user experience, multiple keyboard options, usb connectivity, etc.)
Not every generation of every Apple product is going to be revolutionary, as the iPhone 4S most recently demonstrated. The new iPad had added some incremental value without seriously compromising the excellent features of the iPad 2 at the same price points. That's laudable.